| Feature | Utilities |
|---|---|
| SSH | Dropbear has both an ssh server and an ssh client that together come in around 100k. It has no external dependencies (I.E. it does not depend on OpenSSL, using a built-in copy of LibTomCrypt instead). It's actively maintained, with a quiet but responsive mailing list. |
| SMTP | ssmtp is an extremely simple Mail Transfer Agent. |
| ntp | ntpclient is a tiny ntp client. BusyBox has rdate to set the date from a remote server, but if you want a daemon to repeatedly adjust the clock over time, try that. |
In a gui environment, you'll probably want a web browser. Konqueror Embedded requires QT (or QT Embedded), but not KDE. The Dillo requires GTK+, but not Gnome. Or you can try the graphical version of links.
Although busybox has built-in support for shell scripts, plenty of other small scripting languages are available on the net. A few examples:
| microperl | A small standalone perl interpreter that can be built from the perl source s via "make -f Makefile.micro". If you really feel the need for perl on an embe dded system, this is where to start. |
| Lua | If you just want a small embedded scripting language to write new code in, this Brazilian import is lightweight, fairly popular, and has a complete book about it online. |
| rc | The PLAN9 shell. Not compatible with conventional bourne shell syntax, but fairly lightweight and small. |
| forth | A well known language for fast and small programs, decades old but still in use for everything from OpenBIOS to computer controlled engine timing. |
For more information, you probably want to look at buildroot and TinyGentoo, which build and use tiny utilities for all sorts of things.